Shockwave is always hit or miss for me. I had the same issue this month while going for trophy upgrades. With Attack of the Slorgs, I messed with the window size on accident in my first attempt and closed it out. Then I couldn't get it to load again for the life of me. I don't know how many times I refreshed before it finally worked. Same thing with Hannah etc. I'm using the same Pale Moon/Fiddler setup as you so it does seem to be something amiss!